2011 US91 is an asteroid in the Apollo orbit class. Its orbit takes it from 0.79 AU to 1.28 AU from the Sun; one orbit takes 385.3 days. Orbit from the JPL solution of 15 April 2021.
Where is it now
- Distance from Sun
- 1.283 AU
- True anomaly
- 183.91°
- Distance from Earth
- 1.042 AU
- As of
- 4 November 2026
Two-body Kepler propagation — accurate to ~0.1% for major planets over decades, less so for highly-perturbed bodies. Use JPL Horizons for high precision.
In the sky
- Right ascension
- 10h 58m 45s
- Declination
- +44° 26′ 45″
- Constellation
- Ursa Major
- Distance from Earth
- 1.04 AU
- Elongation from the Sun
- 78.23° — well clear of the Sun
Favours the northern hemisphere; low or below the horizon from far south.
From your location
See how high it is right now, whether it is up after civil twilight, and when it rises and sets where you are.
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Two-body approximation, good to about a degree for the planets — enough to find the constellation and know whether it is up.
Orbital elements
- Semi-major axis
- 1.036 AU
- Eccentricity
- 0.2395
- Inclination
- 29.37°
- Orbital period
- 385.3 days
- Perihelion
- 0.788 AU
- Aphelion
- 1.284 AU
- Longitude of ascending node
- 22.01°
- Argument of periapsis
- 245.96°
- Epoch · J2000
- 2455859.5
- Orbit class · APO
- Apollo
- Earth MOID · 29.1 LD
- 0.0748 AU
- Tisserand (Jupiter)
- 5.777
Orbit quality
Orbit very uncertain — the object may be effectively lost (uncertainty code 8).
- Observations used
- 48
- Data arc
- 11 days
- First observed
- 23 October 2011
- Last observed
- 3 November 2011
- Residual RMS
- 0.38 ″
- Solution · Otto Matic
- 15 April 2021
Visual & observation
- Absolute magnitude (H)
- 22.3
Discovery & classification
Close approaches 12 on record
Top-down view of the ecliptic, Earth at the centre, for the 2181-03-14 10:17 UTC close approach of 2011 US91. Catalogue miss distance 170.6 LD · 6.56 × 10⁷ km. The curve is the geocentric path from 2181-03-11 to 2181-03-17, with a mark at UTC midnights and an arrow for the direction of motion. The circle is the Moon’s mean orbit; the Moon is plotted at closest approach. A ray shows the Sun’s direction. The labelled distance is the full separation. The drawn radius is the part that lies in the ecliptic plane. The path is a geocentric ecliptic ephemeris from JPL Horizons. The inset is a heliocentric view and is approximate.
| When (UTC) | Body | Distance | Lunar distances | Relative speed |
|---|---|---|---|---|
| 2181-03-14 10:17:00 | Earth | 0.4384 AU | 170.6 LD | 25.6 km/s |
| 2182-04-02 08:49:00 | Earth | 0.1451 AU | 56.5 LD | 19 km/s |
| 2183-04-26 10:40:00 | Earth | 0.241 AU | 93.8 LD | 16.2 km/s |
| 2184-10-14 08:43:00 | Earth | 0.2501 AU | 97.3 LD | 14.7 km/s |
| 2185-10-14 04:55:00 | Earth | 0.1007 AU | 39.2 LD | 17.4 km/s |
| 2186-10-22 15:05:00 | Earth | 0.3942 AU | 153.4 LD | 24.1 km/s |
Next ten from today. 1 lunar distance = 384,400 km. Source: JPL close-approach data.
Sources
- visual properties: JPL SBDB (lookup)
- orbital elements: JPL SBDB